The present invention relates to hydrostatic balancing jackets for scuba diving, and refers in particular to an inflatable chamber for hydrostatic balancing jackets.
Balancing jackets usually consist of a back element from which two abdominal breast strips and two shoulder strips extend, the latter being connectable the ones to the others; the balancing jacket is provided with one or more inflatable chambers, usually placed on the abdominal breast strips or on the back element. Generally speaking, apart from the position of the inflatable chamber, what is highly important for the diver's convenient use is the shape said chamber takes after being inflated.
One of the solutions known from the state of the art is shown in FIG. 1A of the enclosed drawings, said solution providing the construction of the inflatable chamber by overlapping two sheets 101 made of flexible material, in which the surfaces along the respective peripheral edges 111 are tight-sealed or glued one to the other. This kind of solution, though very simple from the structural point of view, is disadvantageous from the point of view of the diver's convenience. As a matter of fact, during the inflation the chamber tends to take a substantially round shape and tends to expand against the diver's body, without being possible to re-position it.
In order to overcome this kind of problem it has been provided for balancing jackets whose inflatable chamber is obtained, as shown in FIG. 1B of the drawings, by introducing onto the peripheral edges 111 of the two sheets 101 made of flexible material a side wall 301 which can be refolded on itself when the chamber is deflated. This kind of configuration actually limits the lateral expansion of the inflatable chamber, as can be seen from figure 1C of the enclosed drawings, although it creates several structural and constructive complications, such as the fact that the folding of the side wall 301 must be strictly controlled.
The U.S. Pat. No. 5,385,496 (Seligman) discloses a balancing jacket in which the inflatable chamber, shown in a section view in FIG. 1D, comprises two flat walls 101 made of flexible material, distanced one from the other by means of a folding wall 401 consisting of two strips 411 and 421 also made of flexible material, whose outer peripheral edges 441 are connected to the outer peripheral edge 111 of one of the flat walls 101, whereas the inner peripheral edges 431 are connected one to the other. This embodiment allows the prevention of many problems occurring with the use of the structure previously described; in this case the folding of the wall 401 doesn't have to be controlled because of the presence of a bellows-shaped element guiding the expansion of the inflatable chamber, said element being able, once deflated, to gain its correct position autonomously.
However, also this kind of solution shows some drawbacks, since the connection line between the strips 411 and 421, inserted between the two flat walls 101 and constituting the folding wall 401, undergoes a consistent effort when the chamber is inflated (see FIG. 1E). In addition, said strips must be coated with a heat sealable material, such as plastics or similar material, also on the side facing the outside of the chamber. Anyway, this last contrivance too has a limited effectiveness with respect to the problems arising during manufacturing.